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NOTE ON THE 



OCCURRENCE OF ACTINOCAMAX PLENUS 

 IN THE CHALK OF YORKSHIRE. 



C. THOMPSON, 

 //////. 



Every g"eolog"ist knows that Actiiiocaniax plemis is the charac- 

 teristic fossil of the narrow zone at the top of the Lower Chalk. 

 Every Yorkshire enthusiast knows full well how many a 

 fruitless search has been made to obtain a specimen in his 

 cou nty. 



Mr. Sheppard records this failure in his most interesting- and 

 useful little book — ' Geolog-ical Rambles in East Yorkshire' — in 

 these words : — 'This fossil occurs in fair numbers in the Black 

 Band of Lincolnshire and other counties, several specimens 

 having' been obtained in the quarries at Louth, and even in 

 those at Barton, on the south Humber shore, but hitherto not 

 a sing-le specimen has been obtained north of the Humber.' 



On Saturday, 13th May, while searching- for chalk fossils in 

 the ' Graystones ' pit (according to the Ordnance Survey), known 

 locally as the ' Melton Bottoms ' pit, which is situated in Swan- 

 land Dale, a little to the north of Melton, and 7^ miles west 

 of Hull, I was so fortunate as to find a fairly larg-e fragment of 

 a belemnitoid, which I at once suspected to be a young ' plenus,' 

 for it both resembled the Barton specimens in state of preserva- 

 tion and was found in situ. 



Dr. A. Row^e, of Margate, to whom the specimen was 

 submitted for identification, gave the opinion that there could 

 be no reasonable doubt that it was a fragment of a young 

 ' plenus,' and noted the find as the first in Yorkshire. 



During an excursion of the members of the Hull Geological 

 Society, on 27th May, the 'Graystones' pit was visited and again 

 thoroughly searched, w^hen Dr. Walton, of Hull, found a better 

 specimen which was dug' out in my presence. This was most 

 gratifying', for not only does it confirm my own find, but also 

 shows that now the veil is lifted, other specimens will soon be 

 recorded. 



As I have now seen three specimens in situ, I may be 

 pardoned if I give their exact positions to serve as a guide to 

 other workers. Forming the base of the Black Band, both at 

 Barton and in the 'Graystones' pit, there is a layer of yellowish 



Naturalist, 



